We had the same last month, two blokes cleaned 5000 sq ft of carpet in two hours using something similar to a rug doctor (we watched the cctv playback) No pre vac or agitation or pre- treatment, just detergent in the machine.
They didn't move anything either, no address on the invoice, no van either, they arrived in an estate car.
The carpet looked a state when we arrived, three weeks after being cleaned!
Regards
S